I went to start my 2015 LEAF SL a few days ago and got the error message "T/M System Malfunction". The car would not start or allow me to put in into gear.

I feared that there was something major wrong with the transmission.

Thanks to this forum I leaned that this message is often seen, when the 12 V battery voltage is low, which usually happens when the battery is failing.

Sure enough, my battery (only 3 years old and lives in a mild climate) was only charged to 8.3 volts, which is apparently low enough to totally confuse the computer systems in the car and produce a bogus error message.. Removing the battery, charging it up to 12 volts, and replacing it allowed the car to start normally. Replacing the battery with a new one appears to have completely fixed the problem.

Note that this all happened, while I waited for Nissan Service to call me back. They finally did call back about 8 hours after I had called and requested a call back. The initial Nissan Service person that I talked to suggested that I might be able to jump start the car. This is typical of the things I hear from Nissan Service about my LEAF.

iamchemist wrote:Sure enough, my battery (only 3 years old and lives in a mild climate) was only charged to 8.3 volts, which is apparently low enough to totally confuse the computer systems in the car and produce a bogus error message..

Yeah; bummer. See, most microcomputer systems need something like 3.3V to operate, and while it may someday be possible to derive 3.3V from a raw supply that's fallen from 12V to 8V, it's not reasonable to expect Nissan to pull a miracle like that off just now. And besides; those computers probably need a dozen milliamperes or more to run; not the sort of punch that you could reasonably expect from a battery that's only intended to crank a starter motor. Well, maybe you can when it's in tip-top condition, but not one that's been kept on a starvation diet for a few years. Some might wonder whether, on its way down from 12V to 8V, the system computer could find twenty microseconds to record a trouble code signifying, "hey! my misapplied battery's toast!". Dreamers.

Levenkay wrote:Yeah; bummer. See, most microcomputer systems need something like 3.3V to operate, and while it may someday be possible to derive 3.3V from a raw supply that's fallen from 12V to 8V, it's not reasonable to expect Nissan to pull a miracle like that off just now. And besides; those computers probably need a dozen milliamperes or more to run; not the sort of punch that you could reasonably expect from a battery that's only intended to crank a starter motor. Well, maybe you can when it's in tip-top condition, but not one that's been kept on a starvation diet for a few years. Some might wonder whether, on its way down from 12V to 8V, the system computer could find twenty microseconds to record a trouble code signifying, "hey! my misapplied battery's toast!". Dreamers.

That post is sarcastic gold. Thanks for making my day.

Add to it: It's also a shame that there's no way to remove the 12v battery entirely. If only there were a large battery of sufficient power, we could avoid the lead acid one entirely...